2006-07-26 04:00:00 PDT Sacramento -- Blistering heat has killed thousands of dairy cows in the Central Valley, depressed milk production and put crops such as walnuts and peaches at risk, state agriculture officials said Tuesday.

"Humans take a while to acclimate to the heat, and animals are impacted as well," said Ann Schmidt-Fogarty, a spokeswoman for the California Farm Bureau. "We are doing all we can to protect them. But farmers are scrambling -- I don't think anyone anticipated this number of days when it was this hot."

The large number of dairy cow deaths has overwhelmed the rendering plants that normally dispose of the carcasses.

"If you don't bury them, you have to deal with the stench and flies," said John Ferreira of the Cotta & Ferreira Dairy in Stockton.

Steve Lyle, a spokesman for the department said his agency believes thousands of head of livestock have died, but he could not provide a specific number.

Most of the problems are in the southern Central Valley, including Fresno, Kern and King counties where temperatures have soared above 110 degrees on some days. Some turkey farms in the region have also experienced extensive losses, officials said.

Ferreira lost only one cow and was able to have it disposed of properly, and his dairy farmworkers have been working hard to keep the herd healthy. He has heard of some ranchers burying carcasses on their farms to deal with the problem, something he said most farmers want to avoid because of the possibility of disease.

Milk production is down 20 percent at his farm, Ferreira said. Statewide production is down at least 15 percent, according to the California Farm Bureau.

"Cows don't want to eat as much when it's hot," said Ferreira, who has 300 cows. "They know by eating their body produces more heat. But if they are not eating, they are not producing milk. It goes hand in hand."

Schmidt-Fogarty said she can understand why it's hard for the cows -- her air conditioning was out for a day and it was hard to get things done.

"They need optimum temperatures and need to be really comfortable to give out milk," she said.

Ferreira's farm uses water mist systems to keep the cows cool, although they can't run them all the time for fear of pneumonia. Cows are also being given their hay inside a barn, where it is shady, rather than out in the heat.

"No one knew it was going to be this hot this long," Ferreira said.

Farmers across the state are watching their crops, Schmidt-Fogarty said. Walnut farmers are already reporting signs of sunburn but won't know the full extent of the loss until the crop is harvested.

Peaches, plum and nectarine farmers are seeing some impact, while strawberry and tomato farmers are keeping a close eye on their produce.

The intense heat can ripen peaches and nectarines unevenly or cause sun damage, Schmidt-Fogarty said. It's also hard to get them picked when it is so hot out.

"We don't want workers out there when it's too hot," she said. "So all these things are converging. It's not lucky for farmers."